The bank was accused of deflating or misstating a loss of more than $460 million in its accounting books during a merger last year.
The government said its own accountants would audit the bank for the next two years, the Korea Times reported. The bank also will be required to pay more than $263 million in back taxes.
Samil Accounting, the auditor of Kookmin Bank, will be prohibited from auditing the bank for two years and will be required to set aside 25 percent of the fee it received from the bank for an indemnification fund, the report said.
Next month, the government will determine the punishment for Kookmin's executives including its president Kim Jung-tae.